U.S. Pat. No. 4,183,579 to Enrique M. Gonzalez y Rojas, the applicant herein, ("the '579 patent"hereafter) discloses a stool designed to support a user in near-standing position for extended periods of time while allowing the user to maneuver on the stool without slipping out of place or becoming unstable at any time. For example, during surgical procedures, doctors must often stand for lengthy periods. The stool of the '579 patent is designed to take part of the standing load off the doctor's legs while allowing him to stably lean in his seated position in various directions.
The stool of the '579 patent comprises a seat disposed on an elongated support column which is mounted to a tripod base. The support column provides a spring hinge assembly for allowing inclination of the seat and the support column relative to the tripod base. The spring hinge assembly biases the support column in an upright position.
Using leg movements, the user can incline the stool of the '579 patent and thereby extend his range of motion while maintaining a seated position on the stool. To prevent the stool from tipping during these inclination maneuvers, the outer ends of the tripod base legs provide suction cups to attach securely to the floor.
In addition, a pair of elongated stabilizing members extend from the central portion of the support column of the stool of the '579 patent to the floor outwardly beyond the base legs. The stabilizing members are spaced apart and attached to the support column above the spring hinge assembly by a pivoting and sliding linkage. As such, when the seat and support column are inclined forward or laterally, the lower ends of the stabilizing members slide toward the stool while the upper ends slide up the support column. By following the motion of the support column, the stabilizing members do not interfere with the smooth motion of the stool. During these manuevers, the user's legs provide the stabilizing support otherwise provided by the stabilizing members.
When the stool is returned to a vertical position, the stabilizing members slide down and out to support any load directed to the rear. Hence, the user may apply backward leaning forces without fear of tipping over.
Although the stool of the '579 patent generally provides stability for a range of inclined positions, it has a significant limitation in its support capabilities. Because of the angled positions of the stabilizing members, any lateral inclination of the seat and support member lifts one of the stabilizing members from the floor, thereby reducing stability for the maneuver. Moreover, when the seat is rotated relative to the support column so that the stabilizing members are no longer positioned behind the user, e.g. a 90 degree left or right turn, the stabilizing members no longer prevent the seat from being inclined rearwardly, so that the user can lose his balance.
Accordingly, it is an object of the invention to provide an inclinable stool with a swivel mechanism in which the stabilizing members rotate with the seat to provide maximum stability regardless of the direction of inclination.
The stabilizing members of the stool of the '579 patent are attached to the support column in such a manner that, upon sufficient forward inclination, the lower ends of the stabilizing members strike the legs of the tripod base, causing abrupt jolts which could disturb a doctor's critical hand positioning during surgery.
It is, therefore, another object of the invention to provide a clamp stop on the support column for restricting the motion of the stabilizing members so that they do not strike the base legs and interrupt the rotary motion of the stool.
The seat employed in the stool of the '579 patent has a tapering, generally rectangular form similar to the shape commonly used for bicycle and motorcycle seats. Because this seat design provides no lateral hip and buttocks support, standing loads are concentrated at the center of the user's thighs and buttocks, causing cramping in these muscle groups.
Hence, it is a further object of the present invention to provide an anatomically designed seat for fully supporting the user's upper thighs and buttocks while providing a pair of concavities on the front surface for positioning of the user's legs. As will be shown below, the seat design also provides easier rotation with increased control.
Still another object of this invention is to facilitate manufacture of the stool by providing parts designed for quicker assembly than the '589 stool.